Five-hundred years ago, a 15-year-old Incan girl was sacrificed, along with two other children. Her mummy has now revealed that she had an active lung infection at her death. Because a technique called shotgun proteomics has been used to determine whether someone was actually suffering from a disease rather than just carrying it. The report appears in the journal PLoS ONE. [Angelique Corthals et al., Detecting the Immune System Response of a 500-Year-Old Inca Mummy]

Previous research into ancient diseases has used DNA analysis to determine the presence of pathogens. But with DNA, there's no way to tell latent infections from the full-blown, misery-inducing ones.

Researchers analyzed protein samples from the mummies of two of the slain children. The girl's proteins indicated an immune response to bacteria, perhaps a pathogen related to tuberculosis. Other evidence, such as mucus under her nose and lung abnormalities, strengthened the diagnosis. The seven-year-old boy, on the other hand, showed no signs of infection.

This is the first time the technique has been used. It’s a small sample, but further development of shotgun proteomics has the potential to improve our understanding of ancient disease, as well as assisting in tomorrow’s forensic investigations.